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depth-0"><p class="sidebar-heading open"><span>Vue</span> <span class="arrow down"></span></p> <ul class="sidebar-links sidebar-group-items"><li><a href="/fe/vue/" aria-current="page" class="sidebar-link">Vue的理解</a></li><li><a href="/fe/vue/mvvm.html" class="sidebar-link">MVVM 双向数据绑定</a></li><li><a href="/fe/vue/spa.html" class="sidebar-link">面试官：你对SPA单页面的理解，它的优缺点分别是什么？如何实现SPA应用呢</a></li><li><a href="/fe/vue/show_if.html" class="sidebar-link">v-show 和 v-if 有什么区别？</a></li><li><a href="/fe/vue/new_vue.html" class="sidebar-link">面试官：Vue实例挂载的过程</a></li><li><a href="/fe/vue/lifecycle.html" class="sidebar-link">面试官：请描述下你对vue生命周期的理解？在created和mounted这两个生命周期中请求数据有什么区别呢？</a></li><li><a href="/fe/vue/if_for.html" class="sidebar-link">面试官：v-if和v-for的优先级是什么？</a></li><li><a href="/fe/vue/computed_watch.html" class="sidebar-link">计算属性 VS 监听属性</a></li><li><a href="/fe/vue/first_page_time.html" class="sidebar-link">面试官：SPA首屏加载速度慢的怎么解决？</a></li><li><a href="/fe/vue/data.html" class="sidebar-link">面试官：为什么data属性是一个函数而不是一个对象？</a></li><li><a href="/fe/vue/data_object_add_attrs.html" class="sidebar-link">面试官：动态给vue的data添加一个新的属性时会发生什么？怎样解决？</a></li><li><a href="/fe/vue/components_plugin.html" class="sidebar-link">面试官：Vue中组件和插件有什么区别？</a></li><li><a href="/fe/vue/communication.html" class="sidebar-link">面试官：Vue组件之间的通信方式都有哪些？</a></li><li><a href="/fe/vue/nexttick.html" class="sidebar-link">面试官：Vue中的$nextTick有什么作用？</a></li><li><a href="/fe/vue/mixin.html" class="sidebar-link">Mixin 混入</a></li><li><a href="/fe/vue/slot.html" class="sidebar-link">面试官：说说你对slot的理解？slot使用场景有哪些？</a></li><li><a href="/fe/vue/observable.html" class="sidebar-link">面试官：Vue.observable你有了解过吗？说说看</a></li><li><a href="/fe/vue/key.html" class="sidebar-link">Key的理解</a></li><li><a href="/fe/vue/keepalive.html" class="sidebar-link">面试官：说说你对keep-alive的理解是什么？</a></li><li><a href="/fe/vue/modifier.html" class="sidebar-link">面试官：Vue常用的修饰符有哪些有什么应用场景</a></li><li><a href="/fe/vue/directive.html" class="sidebar-link">面试官：你有写过自定义指令吗？自定义指令的应用场景有哪些？</a></li><li><a href="/fe/vue/filter.html" class="sidebar-link">面试官：Vue中的过滤器了解吗？过滤器的应用场景有哪些？</a></li><li><a href="/fe/vue/vnode.html" aria-current="page" class="active sidebar-link">虚拟DOM</a><ul class="sidebar-sub-headers"><li class="sidebar-sub-header"><a href="/fe/vue/vnode.html#一、什么是虚拟dom" class="sidebar-link">一、什么是虚拟DOM</a></li><li class="sidebar-sub-header"><a href="/fe/vue/vnode.html#二、为什么需要虚拟dom" class="sidebar-link">二、为什么需要虚拟DOM</a></li><li class="sidebar-sub-header"><a href="/fe/vue/vnode.html#三、如何实现虚拟dom" class="sidebar-link">三、如何实现虚拟DOM</a></li><li class="sidebar-sub-header"><a href="/fe/vue/vnode.html#参考文献" class="sidebar-link">参考文献</a></li></ul></li><li><a href="/fe/vue/diff.html" class="sidebar-link">Diff 算法</a></li><li><a href="/fe/vue/axios.html" class="sidebar-link">面试官：Vue项目中有封装过axios吗？主要是封装哪方面的？</a></li><li><a href="/fe/vue/axios_code.html" class="sidebar-link">面试官：你了解axios的原理吗？有看过它的源码吗？</a></li><li><a href="/fe/vue/ssr.html" class="sidebar-link">面试官：SSR解决了什么问题？有做过SSR吗？你是怎么做的？</a></li><li><a href="/fe/vue/structure.html" class="sidebar-link">面试官：说下你的vue项目的目录结构，如果是大型项目你该怎么划分结构和划分组件呢？</a></li><li><a href="/fe/vue/permission.html" class="sidebar-link">面试官：vue要做权限管理该怎么做？如果控制到按钮级别的权限怎么做？</a></li><li><a href="/fe/vue/cors.html" class="sidebar-link">面试官：Vue项目中你是如何解决跨域的呢？</a></li><li><a href="/fe/vue/404.html" class="sidebar-link">面试官：vue项目本地开发完成后部署到服务器后报404是什么原因呢？</a></li><li><a href="/fe/vue/error.html" class="sidebar-link">面试官：你是怎么处理vue项目中的错误的？</a></li><li><a href="/fe/vue/vue_router.html" class="sidebar-link">Vue Router</a></li><li><a href="/fe/vue/vue-debounce-throttle.html" class="sidebar-link">vue防抖调研</a></li></ul></section></li><li><section class="sidebar-group collapsable depth-0"><p class="sidebar-heading"><span>Vue3</span> <span class="arrow right"></span></p> <!----></section></li><li><section class="sidebar-group collapsable depth-0"><p class="sidebar-heading"><span>React</span> <span class="arrow right"></span></p> <!----></section></li><li><section class="sidebar-group collapsable depth-0"><p class="sidebar-heading"><span>Webpack</span> <span class="arrow right"></span></p> <!----></section></li><li><section class="sidebar-group collapsable depth-0"><p class="sidebar-heading"><span>Node.js</span> <span class="arrow right"></span></p> <!----></section></li><li><section class="sidebar-group collapsable depth-0"><p class="sidebar-heading"><span>性能优化</span> <span class="arrow right"></span></p> <!----></section></li><li><section class="sidebar-group collapsable depth-0"><p class="sidebar-heading"><span>手写代码</span> <span class="arrow right"></span></p> <!----></section></li></ul> </aside> <main class="page"> <div class="theme-default-content content__default"><h1 id="虚拟dom"><a href="#虚拟dom" class="header-anchor">#</a> 虚拟DOM</h1> <p><img src="https://static.vue-js.com/770b9670-442c-11eb-85f6-6fac77c0c9b3.png" alt=""></p> <h2 id="一、什么是虚拟dom"><a href="#一、什么是虚拟dom" class="header-anchor">#</a> 一、什么是虚拟DOM</h2> <p>虚拟 DOM （<code>Virtual DOM</code> ）这个概念相信大家都不陌生，从 <code>React</code> 到 <code>Vue</code> ，虚拟 <code>DOM</code> 为这两个框架都带来了跨平台的能力（<code>React-Native</code> 和 <code>Weex</code>）</p> <p>实际上它只是一层对真实<code>DOM</code>的抽象，以<code>JavaScript</code> 对象 (<code>VNode</code> 节点) 作为基础的树，用对象的属性来描述节点，最终可以通过一系列操作使这棵树映射到真实环境上</p> <p>在<code>Javascript</code>对象中，虚拟<code>DOM</code> 表现为一个 <code>Object</code>对象。并且最少包含标签名 (<code>tag</code>)、属性 (<code>attrs</code>) 和子元素对象 (<code>children</code>) 三个属性，不同框架对这三个属性的名命可能会有差别</p> <p>创建虚拟<code>DOM</code>就是为了更好将虚拟的节点渲染到页面视图中，所以虚拟<code>DOM</code>对象的节点与真实<code>DOM</code>的属性一一照应</p> <p>在<code>vue</code>中同样使用到了虚拟<code>DOM</code>技术。定义真实<code>DOM</code></p> <div class="language-html extra-class"><pre class="language-html"><code><span class="token tag"><span class="token tag"><span class="token punctuation">&lt;</span>div</span> <span class="token attr-name">id</span><span class="token attr-value"><span class="token punctuation attr-equals">=</span><span class="token punctuation">&quot;</span>app<span class="token punctuation">&quot;</span></span><span class="token punctuation">&gt;</span></span>
    <span class="token tag"><span class="token tag"><span class="token punctuation">&lt;</span>p</span> <span class="token attr-name">class</span><span class="token attr-value"><span class="token punctuation attr-equals">=</span><span class="token punctuation">&quot;</span>p<span class="token punctuation">&quot;</span></span><span class="token punctuation">&gt;</span></span>节点内容<span class="token tag"><span class="token tag"><span class="token punctuation">&lt;/</span>p</span><span class="token punctuation">&gt;</span></span>
    <span class="token tag"><span class="token tag"><span class="token punctuation">&lt;</span>h3</span><span class="token punctuation">&gt;</span></span>{{ foo }}<span class="token tag"><span class="token tag"><span class="token punctuation">&lt;/</span>h3</span><span class="token punctuation">&gt;</span></span>
<span class="token tag"><span class="token tag"><span class="token punctuation">&lt;/</span>div</span><span class="token punctuation">&gt;</span></span>
</code></pre></div><p>实例化<code>vue</code></p> <div class="language-js extra-class"><pre class="language-js"><code><span class="token keyword">const</span> app <span class="token operator">=</span> <span class="token keyword">new</span> <span class="token class-name">Vue</span><span class="token punctuation">(</span><span class="token punctuation">{</span>
    el<span class="token operator">:</span><span class="token string">&quot;#app&quot;</span><span class="token punctuation">,</span>
    data<span class="token operator">:</span><span class="token punctuation">{</span>
        foo<span class="token operator">:</span><span class="token string">&quot;foo&quot;</span>
    <span class="token punctuation">}</span>
<span class="token punctuation">}</span><span class="token punctuation">)</span>
</code></pre></div><p>观察<code>render</code>的<code>render</code>，我们能得到虚拟<code>DOM</code></p> <div class="language-js extra-class"><pre class="language-js"><code><span class="token punctuation">(</span><span class="token keyword">function</span> <span class="token function">anonymous</span><span class="token punctuation">(</span>
<span class="token punctuation">)</span> <span class="token punctuation">{</span>
	<span class="token keyword">with</span><span class="token punctuation">(</span><span class="token keyword">this</span><span class="token punctuation">)</span><span class="token punctuation">{</span><span class="token keyword">return</span> <span class="token function">_c</span><span class="token punctuation">(</span><span class="token string">'div'</span><span class="token punctuation">,</span><span class="token punctuation">{</span>attrs<span class="token operator">:</span><span class="token punctuation">{</span><span class="token string">&quot;id&quot;</span><span class="token operator">:</span><span class="token string">&quot;app&quot;</span><span class="token punctuation">}</span><span class="token punctuation">}</span><span class="token punctuation">,</span><span class="token punctuation">[</span><span class="token function">_c</span><span class="token punctuation">(</span><span class="token string">'p'</span><span class="token punctuation">,</span><span class="token punctuation">{</span>staticClass<span class="token operator">:</span><span class="token string">&quot;p&quot;</span><span class="token punctuation">}</span><span class="token punctuation">,</span>
					  <span class="token punctuation">[</span><span class="token function">_v</span><span class="token punctuation">(</span><span class="token string">&quot;节点内容&quot;</span><span class="token punctuation">)</span><span class="token punctuation">]</span><span class="token punctuation">)</span><span class="token punctuation">,</span><span class="token function">_v</span><span class="token punctuation">(</span><span class="token string">&quot; &quot;</span><span class="token punctuation">)</span><span class="token punctuation">,</span><span class="token function">_c</span><span class="token punctuation">(</span><span class="token string">'h3'</span><span class="token punctuation">,</span><span class="token punctuation">[</span><span class="token function">_v</span><span class="token punctuation">(</span><span class="token function">_s</span><span class="token punctuation">(</span>foo<span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">]</span><span class="token punctuation">)</span><span class="token punctuation">]</span><span class="token punctuation">)</span><span class="token punctuation">}</span><span class="token punctuation">}</span><span class="token punctuation">)</span>
</code></pre></div><p>通过<code>VNode</code>，<code>vue</code>可以对这颗抽象树进行创建节点,删除节点以及修改节点的操作， 经过<code>diff</code>算法得出一些需要修改的最小单位,再更新视图，减少了<code>dom</code>操作，提高了性能</p> <h3 id="实现原理"><a href="#实现原理" class="header-anchor">#</a> 实现原理：</h3> <ol><li>虚拟DOM本质上是JavaScript对象,是对真实DOM的抽象</li> <li>状态变更时，记录新树和旧树的差异</li> <li>最后把差异更新到真正的DOM中</li></ol> <h3 id="优点"><a href="#优点" class="header-anchor">#</a> 优点:</h3> <ol><li>保证性能下限：虚拟DOM可以经过 <code>diff</code> 算法找出最小差异，然后进行批量 <code>patch</code>，这种操作虽然比不上手动优化，但是比起粗暴的DOM操作性能要好很多，因此虚拟DOM可以保证性能下限。</li> <li>无需手动操作DOM：虚拟DOM的 <code>diff</code> 和 <code>patch</code> 都是在一次更新中自动进行的，我们无需手动操作DOM，极大提高开发效率。</li> <li>跨平台: 虚拟DOM本质上是JavaScript对象，而DOM与平台强相关，相比之下虚拟DOM可以进行更方便地跨平台操作，例如服务器渲染、移动端开发等等。</li></ol> <h3 id="缺点"><a href="#缺点" class="header-anchor">#</a> 缺点:</h3> <ol><li>无法进行极致优化：在一些性能要求极高的应用中虚拟DOM无法进行针对性的极致优化，比如VScode采用直接手动操作DOM的方式进行极端的性能优化。</li></ol> <h2 id="二、为什么需要虚拟dom"><a href="#二、为什么需要虚拟dom" class="header-anchor">#</a> 二、为什么需要虚拟DOM</h2> <p><code>DOM</code>是很慢的，其元素非常庞大，页面的性能问题，大部分都是由<code>DOM</code>操作引起的</p> <p>真实的<code>DOM</code>节点，哪怕一个最简单的<code>div</code>也包含着很多属性，可以打印出来直观感受一下：
<img src="https://static.vue-js.com/cc95c7f0-442c-11eb-ab90-d9ae814b240d.png" alt=""></p> <p>由此可见，操作<code>DOM</code>的代价仍旧是昂贵的，频繁操作还是会出现页面卡顿，影响用户的体验</p> <p><strong>举个例子：</strong></p> <p>你用传统的原生<code>api</code>或<code>jQuery</code>去操作<code>DOM</code>时，浏览器会从构建<code>DOM</code>树开始从头到尾执行一遍流程</p> <p>当你在一次操作时，需要更新10个<code>DOM</code>节点，浏览器没这么智能，收到第一个更新<code>DOM</code>请求后，并不知道后续还有9次更新操作，因此会马上执行流程，最终执行10次流程</p> <p>而通过<code>VNode</code>，同样更新10个<code>DOM</code>节点，虚拟<code>DOM</code>不会立即操作<code>DOM</code>，而是将这10次更新的<code>diff</code>内容保存到本地的一个<code>js</code>对象中，最终将这个<code>js</code>对象一次性<code>attach</code>到<code>DOM</code>树上，避免大量的无谓计算</p> <blockquote><p>很多人认为虚拟 DOM 最大的优势是 diff 算法，减少 JavaScript 操作真实 DOM 的带来的性能消耗。虽然这一个虚拟 DOM 带来的一个优势，但并不是全部。虚拟 DOM 最大的优势在于抽象了原本的渲染过程，实现了跨平台的能力，而不仅仅局限于浏览器的 DOM，可以是安卓和 IOS 的原生组件，可以是近期很火热的小程序，也可以是各种GUI</p></blockquote> <h2 id="三、如何实现虚拟dom"><a href="#三、如何实现虚拟dom" class="header-anchor">#</a> 三、如何实现虚拟DOM</h2> <p>首先可以看看<code>vue</code>中<code>VNode</code>的结构</p> <p>源码位置：src/core/vdom/vnode.js</p> <div class="language-js extra-class"><pre class="language-js"><code><span class="token keyword">export</span> <span class="token keyword">default</span> <span class="token keyword">class</span> <span class="token class-name">VNode</span> <span class="token punctuation">{</span>
  tag<span class="token operator">:</span> string <span class="token operator">|</span> <span class="token keyword">void</span><span class="token punctuation">;</span>
  data<span class="token operator">:</span> VNodeData <span class="token operator">|</span> <span class="token keyword">void</span><span class="token punctuation">;</span>
  children<span class="token operator">:</span> <span class="token operator">?</span>Array<span class="token operator">&lt;</span>VNode<span class="token operator">&gt;</span><span class="token punctuation">;</span>
  text<span class="token operator">:</span> string <span class="token operator">|</span> <span class="token keyword">void</span><span class="token punctuation">;</span>
  elm<span class="token operator">:</span> Node <span class="token operator">|</span> <span class="token keyword">void</span><span class="token punctuation">;</span>
  ns<span class="token operator">:</span> string <span class="token operator">|</span> <span class="token keyword">void</span><span class="token punctuation">;</span>
  context<span class="token operator">:</span> Component <span class="token operator">|</span> <span class="token keyword">void</span><span class="token punctuation">;</span> <span class="token comment">// rendered in this component's scope</span>
  functionalContext<span class="token operator">:</span> Component <span class="token operator">|</span> <span class="token keyword">void</span><span class="token punctuation">;</span> <span class="token comment">// only for functional component root nodes</span>
  key<span class="token operator">:</span> string <span class="token operator">|</span> number <span class="token operator">|</span> <span class="token keyword">void</span><span class="token punctuation">;</span>
  componentOptions<span class="token operator">:</span> VNodeComponentOptions <span class="token operator">|</span> <span class="token keyword">void</span><span class="token punctuation">;</span>
  componentInstance<span class="token operator">:</span> Component <span class="token operator">|</span> <span class="token keyword">void</span><span class="token punctuation">;</span> <span class="token comment">// component instance</span>
  parent<span class="token operator">:</span> VNode <span class="token operator">|</span> <span class="token keyword">void</span><span class="token punctuation">;</span> <span class="token comment">// component placeholder node</span>
  raw<span class="token operator">:</span> boolean<span class="token punctuation">;</span> <span class="token comment">// contains raw HTML? (server only)</span>
  isStatic<span class="token operator">:</span> boolean<span class="token punctuation">;</span> <span class="token comment">// hoisted static node</span>
  isRootInsert<span class="token operator">:</span> boolean<span class="token punctuation">;</span> <span class="token comment">// necessary for enter transition check</span>
  isComment<span class="token operator">:</span> boolean<span class="token punctuation">;</span> <span class="token comment">// empty comment placeholder?</span>
  isCloned<span class="token operator">:</span> boolean<span class="token punctuation">;</span> <span class="token comment">// is a cloned node?</span>
  isOnce<span class="token operator">:</span> boolean<span class="token punctuation">;</span> <span class="token comment">// is a v-once node?</span>

  <span class="token function">constructor</span> <span class="token punctuation">(</span>
    <span class="token parameter">tag<span class="token operator">?</span><span class="token operator">:</span> string<span class="token punctuation">,</span>
    data<span class="token operator">?</span><span class="token operator">:</span> VNodeData<span class="token punctuation">,</span>
    children<span class="token operator">?</span><span class="token operator">:</span> <span class="token operator">?</span>Array<span class="token operator">&lt;</span>VNode<span class="token operator">&gt;</span><span class="token punctuation">,</span>
    text<span class="token operator">?</span><span class="token operator">:</span> string<span class="token punctuation">,</span>
    elm<span class="token operator">?</span><span class="token operator">:</span> Node<span class="token punctuation">,</span>
    context<span class="token operator">?</span><span class="token operator">:</span> Component<span class="token punctuation">,</span>
    componentOptions<span class="token operator">?</span><span class="token operator">:</span> VNodeComponentOptions</span>
  <span class="token punctuation">)</span> <span class="token punctuation">{</span>
    <span class="token comment">/*当前节点的标签名*/</span>
    <span class="token keyword">this</span><span class="token punctuation">.</span>tag <span class="token operator">=</span> tag
    <span class="token comment">/*当前节点对应的对象，包含了具体的一些数据信息，是一个VNodeData类型，可以参考VNodeData类型中的数据信息*/</span>
    <span class="token keyword">this</span><span class="token punctuation">.</span>data <span class="token operator">=</span> data
    <span class="token comment">/*当前节点的子节点，是一个数组*/</span>
    <span class="token keyword">this</span><span class="token punctuation">.</span>children <span class="token operator">=</span> children
    <span class="token comment">/*当前节点的文本*/</span>
    <span class="token keyword">this</span><span class="token punctuation">.</span>text <span class="token operator">=</span> text
    <span class="token comment">/*当前虚拟节点对应的真实dom节点*/</span>
    <span class="token keyword">this</span><span class="token punctuation">.</span>elm <span class="token operator">=</span> elm
    <span class="token comment">/*当前节点的名字空间*/</span>
    <span class="token keyword">this</span><span class="token punctuation">.</span>ns <span class="token operator">=</span> <span class="token keyword">undefined</span>
    <span class="token comment">/*编译作用域*/</span>
    <span class="token keyword">this</span><span class="token punctuation">.</span>context <span class="token operator">=</span> context
    <span class="token comment">/*函数化组件作用域*/</span>
    <span class="token keyword">this</span><span class="token punctuation">.</span>functionalContext <span class="token operator">=</span> <span class="token keyword">undefined</span>
    <span class="token comment">/*节点的key属性，被当作节点的标志，用以优化*/</span>
    <span class="token keyword">this</span><span class="token punctuation">.</span>key <span class="token operator">=</span> data <span class="token operator">&amp;&amp;</span> data<span class="token punctuation">.</span>key
    <span class="token comment">/*组件的option选项*/</span>
    <span class="token keyword">this</span><span class="token punctuation">.</span>componentOptions <span class="token operator">=</span> componentOptions
    <span class="token comment">/*当前节点对应的组件的实例*/</span>
    <span class="token keyword">this</span><span class="token punctuation">.</span>componentInstance <span class="token operator">=</span> <span class="token keyword">undefined</span>
    <span class="token comment">/*当前节点的父节点*/</span>
    <span class="token keyword">this</span><span class="token punctuation">.</span>parent <span class="token operator">=</span> <span class="token keyword">undefined</span>
    <span class="token comment">/*简而言之就是是否为原生HTML或只是普通文本，innerHTML的时候为true，textContent的时候为false*/</span>
    <span class="token keyword">this</span><span class="token punctuation">.</span>raw <span class="token operator">=</span> <span class="token boolean">false</span>
    <span class="token comment">/*静态节点标志*/</span>
    <span class="token keyword">this</span><span class="token punctuation">.</span>isStatic <span class="token operator">=</span> <span class="token boolean">false</span>
    <span class="token comment">/*是否作为跟节点插入*/</span>
    <span class="token keyword">this</span><span class="token punctuation">.</span>isRootInsert <span class="token operator">=</span> <span class="token boolean">true</span>
    <span class="token comment">/*是否为注释节点*/</span>
    <span class="token keyword">this</span><span class="token punctuation">.</span>isComment <span class="token operator">=</span> <span class="token boolean">false</span>
    <span class="token comment">/*是否为克隆节点*/</span>
    <span class="token keyword">this</span><span class="token punctuation">.</span>isCloned <span class="token operator">=</span> <span class="token boolean">false</span>
    <span class="token comment">/*是否有v-once指令*/</span>
    <span class="token keyword">this</span><span class="token punctuation">.</span>isOnce <span class="token operator">=</span> <span class="token boolean">false</span>
  <span class="token punctuation">}</span>

  <span class="token comment">// DEPRECATED: alias for componentInstance for backwards compat.</span>
  <span class="token comment">/* istanbul ignore next https://github.com/answershuto/learnVue*/</span>
  <span class="token keyword">get</span> <span class="token function">child</span> <span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token operator">:</span> Component <span class="token operator">|</span> <span class="token keyword">void</span> <span class="token punctuation">{</span>
    <span class="token keyword">return</span> <span class="token keyword">this</span><span class="token punctuation">.</span>componentInstance
  <span class="token punctuation">}</span>
<span class="token punctuation">}</span>
</code></pre></div><p>这里对<code>VNode</code>进行稍微的说明：</p> <ul><li>所有对象的 <code>context</code> 选项都指向了 <code>Vue</code> 实例</li> <li><code>elm</code> 属性则指向了其相对应的真实 <code>DOM</code> 节点</li></ul> <p><code>vue</code>是通过<code>createElement</code>生成<code>VNode</code></p> <p>源码位置：src/core/vdom/create-element.js</p> <div class="language-js extra-class"><pre class="language-js"><code><span class="token keyword">export</span> <span class="token keyword">function</span> <span class="token function">createElement</span> <span class="token punctuation">(</span>
  <span class="token parameter">context<span class="token operator">:</span> Component<span class="token punctuation">,</span>
  tag<span class="token operator">:</span> any<span class="token punctuation">,</span>
  data<span class="token operator">:</span> any<span class="token punctuation">,</span>
  children<span class="token operator">:</span> any<span class="token punctuation">,</span>
  normalizationType<span class="token operator">:</span> any<span class="token punctuation">,</span>
  alwaysNormalize<span class="token operator">:</span> boolean</span>
<span class="token punctuation">)</span><span class="token operator">:</span> VNode <span class="token operator">|</span> Array<span class="token operator">&lt;</span>VNode<span class="token operator">&gt;</span> <span class="token punctuation">{</span>
  <span class="token keyword">if</span> <span class="token punctuation">(</span>Array<span class="token punctuation">.</span><span class="token function">isArray</span><span class="token punctuation">(</span>data<span class="token punctuation">)</span> <span class="token operator">||</span> <span class="token function">isPrimitive</span><span class="token punctuation">(</span>data<span class="token punctuation">)</span><span class="token punctuation">)</span> <span class="token punctuation">{</span>
    normalizationType <span class="token operator">=</span> children
    children <span class="token operator">=</span> data
    data <span class="token operator">=</span> <span class="token keyword">undefined</span>
  <span class="token punctuation">}</span>
  <span class="token keyword">if</span> <span class="token punctuation">(</span><span class="token function">isTrue</span><span class="token punctuation">(</span>alwaysNormalize<span class="token punctuation">)</span><span class="token punctuation">)</span> <span class="token punctuation">{</span>
    normalizationType <span class="token operator">=</span> <span class="token constant">ALWAYS_NORMALIZE</span>
  <span class="token punctuation">}</span>
  <span class="token keyword">return</span> <span class="token function">_createElement</span><span class="token punctuation">(</span>context<span class="token punctuation">,</span> tag<span class="token punctuation">,</span> data<span class="token punctuation">,</span> children<span class="token punctuation">,</span> normalizationType<span class="token punctuation">)</span>
<span class="token punctuation">}</span>
</code></pre></div><p>上面可以看到<code>createElement</code> 方法实际上是对 <code>_createElement</code> 方法的封装，对参数的传入进行了判断</p> <div class="language-javascript extra-class"><pre class="language-javascript"><code><span class="token keyword">export</span> <span class="token keyword">function</span> <span class="token function">_createElement</span><span class="token punctuation">(</span>
    <span class="token parameter">context<span class="token operator">:</span> Component<span class="token punctuation">,</span>
    tag<span class="token operator">?</span><span class="token operator">:</span> string <span class="token operator">|</span> Class<span class="token operator">&lt;</span>Component<span class="token operator">&gt;</span> <span class="token operator">|</span> Function <span class="token operator">|</span> Object<span class="token punctuation">,</span>
    data<span class="token operator">?</span><span class="token operator">:</span> VNodeData<span class="token punctuation">,</span>
    children<span class="token operator">?</span><span class="token operator">:</span> any<span class="token punctuation">,</span>
    normalizationType<span class="token operator">?</span><span class="token operator">:</span> number</span>
<span class="token punctuation">)</span><span class="token operator">:</span> VNode <span class="token operator">|</span> Array<span class="token operator">&lt;</span>VNode<span class="token operator">&gt;</span> <span class="token punctuation">{</span>
    <span class="token keyword">if</span> <span class="token punctuation">(</span><span class="token function">isDef</span><span class="token punctuation">(</span>data<span class="token punctuation">)</span> <span class="token operator">&amp;&amp;</span> <span class="token function">isDef</span><span class="token punctuation">(</span><span class="token punctuation">(</span>data<span class="token operator">:</span> any<span class="token punctuation">)</span><span class="token punctuation">.</span>__ob__<span class="token punctuation">)</span><span class="token punctuation">)</span> <span class="token punctuation">{</span>
        process<span class="token punctuation">.</span>env<span class="token punctuation">.</span><span class="token constant">NODE_ENV</span> <span class="token operator">!==</span> <span class="token string">'production'</span> <span class="token operator">&amp;&amp;</span> <span class="token function">warn</span><span class="token punctuation">(</span>
            <span class="token template-string"><span class="token template-punctuation string">`</span><span class="token string">Avoid using observed data object as vnode data: </span><span class="token interpolation"><span class="token interpolation-punctuation punctuation">${</span><span class="token constant">JSON</span><span class="token punctuation">.</span><span class="token function">stringify</span><span class="token punctuation">(</span>data<span class="token punctuation">)</span><span class="token interpolation-punctuation punctuation">}</span></span><span class="token string">\n</span><span class="token template-punctuation string">`</span></span> <span class="token operator">+</span>
            <span class="token string">'Always create fresh vnode data objects in each render!'</span><span class="token punctuation">,</span>
            context`
        <span class="token punctuation">)</span>
        <span class="token keyword">return</span> <span class="token function">createEmptyVNode</span><span class="token punctuation">(</span><span class="token punctuation">)</span>
    <span class="token punctuation">}</span>
    <span class="token comment">// object syntax in v-bind</span>
    <span class="token keyword">if</span> <span class="token punctuation">(</span><span class="token function">isDef</span><span class="token punctuation">(</span>data<span class="token punctuation">)</span> <span class="token operator">&amp;&amp;</span> <span class="token function">isDef</span><span class="token punctuation">(</span>data<span class="token punctuation">.</span>is<span class="token punctuation">)</span><span class="token punctuation">)</span> <span class="token punctuation">{</span>
        tag <span class="token operator">=</span> data<span class="token punctuation">.</span>is
    <span class="token punctuation">}</span>
    <span class="token keyword">if</span> <span class="token punctuation">(</span><span class="token operator">!</span>tag<span class="token punctuation">)</span> <span class="token punctuation">{</span>
        <span class="token comment">// in case of component :is set to falsy value</span>
        <span class="token keyword">return</span> <span class="token function">createEmptyVNode</span><span class="token punctuation">(</span><span class="token punctuation">)</span>
    <span class="token punctuation">}</span>
    <span class="token operator">...</span> 
    <span class="token comment">// support single function children as default scoped slot</span>
    <span class="token keyword">if</span> <span class="token punctuation">(</span>Array<span class="token punctuation">.</span><span class="token function">isArray</span><span class="token punctuation">(</span>children<span class="token punctuation">)</span> <span class="token operator">&amp;&amp;</span>
        <span class="token keyword">typeof</span> children<span class="token punctuation">[</span><span class="token number">0</span><span class="token punctuation">]</span> <span class="token operator">===</span> <span class="token string">'function'</span>
    <span class="token punctuation">)</span> <span class="token punctuation">{</span>
        data <span class="token operator">=</span> data <span class="token operator">||</span> <span class="token punctuation">{</span><span class="token punctuation">}</span>
        data<span class="token punctuation">.</span>scopedSlots <span class="token operator">=</span> <span class="token punctuation">{</span> <span class="token keyword">default</span><span class="token operator">:</span> children<span class="token punctuation">[</span><span class="token number">0</span><span class="token punctuation">]</span> <span class="token punctuation">}</span>
        children<span class="token punctuation">.</span>length <span class="token operator">=</span> <span class="token number">0</span>
    <span class="token punctuation">}</span>
    <span class="token keyword">if</span> <span class="token punctuation">(</span>normalizationType <span class="token operator">===</span> <span class="token constant">ALWAYS_NORMALIZE</span><span class="token punctuation">)</span> <span class="token punctuation">{</span>
        children <span class="token operator">=</span> <span class="token function">normalizeChildren</span><span class="token punctuation">(</span>children<span class="token punctuation">)</span>
    <span class="token punctuation">}</span> <span class="token keyword">else</span> <span class="token keyword">if</span> <span class="token punctuation">(</span> <span class="token operator">===</span> <span class="token constant">SIMPLE_NORMALIZE</span><span class="token punctuation">)</span> <span class="token punctuation">{</span>
        children <span class="token operator">=</span> <span class="token function">simpleNormalizeChildren</span><span class="token punctuation">(</span>children<span class="token punctuation">)</span>
    <span class="token punctuation">}</span>
	<span class="token comment">// 创建VNode</span>
    <span class="token operator">...</span>
<span class="token punctuation">}</span>
</code></pre></div><p>可以看到<code>_createElement</code>接收5个参数：</p> <ul><li><p><code>context</code> 表示 <code>VNode</code> 的上下文环境，是 <code>Component</code> 类型</p></li> <li><p>tag 表示标签，它可以是一个字符串，也可以是一个 <code>Component</code></p></li> <li><p><code>data</code> 表示 <code>VNode</code> 的数据，它是一个 <code>VNodeData</code> 类型</p></li> <li><p><code>children</code> 表示当前 <code>VNode</code>的子节点，它是任意类型的</p></li> <li><p><code>normalizationType</code> 表示子节点规范的类型，类型不同规范的方法也就不一样，主要是参考 <code>render</code> 函数是编译生成的还是用户手写的</p></li></ul> <p>根据<code>normalizationType</code> 的类型，<code>children</code>会有不同的定义</p> <div class="language-js extra-class"><pre class="language-js"><code><span class="token keyword">if</span> <span class="token punctuation">(</span>normalizationType <span class="token operator">===</span> <span class="token constant">ALWAYS_NORMALIZE</span><span class="token punctuation">)</span> <span class="token punctuation">{</span>
    children <span class="token operator">=</span> <span class="token function">normalizeChildren</span><span class="token punctuation">(</span>children<span class="token punctuation">)</span>
<span class="token punctuation">}</span> <span class="token keyword">else</span> <span class="token keyword">if</span> <span class="token punctuation">(</span> <span class="token operator">===</span> <span class="token constant">SIMPLE_NORMALIZE</span><span class="token punctuation">)</span> <span class="token punctuation">{</span>
    children <span class="token operator">=</span> <span class="token function">simpleNormalizeChildren</span><span class="token punctuation">(</span>children<span class="token punctuation">)</span>
<span class="token punctuation">}</span>
</code></pre></div><p><code>simpleNormalizeChildren</code>方法调用场景是 <code>render</code> 函数是编译生成的</p> <p><code>normalizeChildren</code>方法调用场景分为下面两种：</p> <ul><li><code>render</code> 函数是用户手写的</li> <li>编译 <code>slot</code>、<code>v-for</code> 的时候会产生嵌套数组</li></ul> <p>无论是<code>simpleNormalizeChildren</code>还是<code>normalizeChildren</code>都是对<code>children</code>进行规范（使<code>children</code> 变成了一个类型为 <code>VNode</code> 的 <code>Array</code>），这里就不展开说了</p> <p>规范化<code>children</code>的源码位置在：src/core/vdom/helpers/normalzie-children.js</p> <p>在规范化<code>children</code>后，就去创建<code>VNode</code></p> <div class="language-js extra-class"><pre class="language-js"><code><span class="token keyword">let</span> vnode<span class="token punctuation">,</span> ns
<span class="token comment">// 对tag进行判断</span>
<span class="token keyword">if</span> <span class="token punctuation">(</span><span class="token keyword">typeof</span> tag <span class="token operator">===</span> <span class="token string">'string'</span><span class="token punctuation">)</span> <span class="token punctuation">{</span>
  <span class="token keyword">let</span> Ctor
  ns <span class="token operator">=</span> <span class="token punctuation">(</span>context<span class="token punctuation">.</span>$vnode <span class="token operator">&amp;&amp;</span> context<span class="token punctuation">.</span>$vnode<span class="token punctuation">.</span>ns<span class="token punctuation">)</span> <span class="token operator">||</span> config<span class="token punctuation">.</span><span class="token function">getTagNamespace</span><span class="token punctuation">(</span>tag<span class="token punctuation">)</span>
  <span class="token keyword">if</span> <span class="token punctuation">(</span>config<span class="token punctuation">.</span><span class="token function">isReservedTag</span><span class="token punctuation">(</span>tag<span class="token punctuation">)</span><span class="token punctuation">)</span> <span class="token punctuation">{</span>
    <span class="token comment">// 如果是内置的节点，则直接创建一个普通VNode</span>
    vnode <span class="token operator">=</span> <span class="token keyword">new</span> <span class="token class-name">VNode</span><span class="token punctuation">(</span>
      config<span class="token punctuation">.</span><span class="token function">parsePlatformTagName</span><span class="token punctuation">(</span>tag<span class="token punctuation">)</span><span class="token punctuation">,</span> data<span class="token punctuation">,</span> children<span class="token punctuation">,</span>
      <span class="token keyword">undefined</span><span class="token punctuation">,</span> <span class="token keyword">undefined</span><span class="token punctuation">,</span> context
    <span class="token punctuation">)</span>
  <span class="token punctuation">}</span> <span class="token keyword">else</span> <span class="token keyword">if</span> <span class="token punctuation">(</span><span class="token function">isDef</span><span class="token punctuation">(</span>Ctor <span class="token operator">=</span> <span class="token function">resolveAsset</span><span class="token punctuation">(</span>context<span class="token punctuation">.</span>$options<span class="token punctuation">,</span> <span class="token string">'components'</span><span class="token punctuation">,</span> tag<span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">)</span> <span class="token punctuation">{</span>
    <span class="token comment">// component</span>
    <span class="token comment">// 如果是component类型，则会通过createComponent创建VNode节点</span>
    vnode <span class="token operator">=</span> <span class="token function">createComponent</span><span class="token punctuation">(</span>Ctor<span class="token punctuation">,</span> data<span class="token punctuation">,</span> context<span class="token punctuation">,</span> children<span class="token punctuation">,</span> tag<span class="token punctuation">)</span>
  <span class="token punctuation">}</span> <span class="token keyword">else</span> <span class="token punctuation">{</span>
    vnode <span class="token operator">=</span> <span class="token keyword">new</span> <span class="token class-name">VNode</span><span class="token punctuation">(</span>
      tag<span class="token punctuation">,</span> data<span class="token punctuation">,</span> children<span class="token punctuation">,</span>
      <span class="token keyword">undefined</span><span class="token punctuation">,</span> <span class="token keyword">undefined</span><span class="token punctuation">,</span> context
    <span class="token punctuation">)</span>
  <span class="token punctuation">}</span>
<span class="token punctuation">}</span> <span class="token keyword">else</span> <span class="token punctuation">{</span>
  <span class="token comment">// direct component options / constructor</span>
  vnode <span class="token operator">=</span> <span class="token function">createComponent</span><span class="token punctuation">(</span>tag<span class="token punctuation">,</span> data<span class="token punctuation">,</span> context<span class="token punctuation">,</span> children<span class="token punctuation">)</span>
<span class="token punctuation">}</span>
</code></pre></div><p><code>createComponent</code>同样是创建<code>VNode</code></p> <p>源码位置：src/core/vdom/create-component.js</p> <div class="language-js extra-class"><pre class="language-js"><code><span class="token keyword">export</span> <span class="token keyword">function</span> <span class="token function">createComponent</span> <span class="token punctuation">(</span>
  <span class="token parameter">Ctor<span class="token operator">:</span> Class<span class="token operator">&lt;</span>Component<span class="token operator">&gt;</span> <span class="token operator">|</span> Function <span class="token operator">|</span> Object <span class="token operator">|</span> <span class="token keyword">void</span><span class="token punctuation">,</span>
  data<span class="token operator">:</span> <span class="token operator">?</span>VNodeData<span class="token punctuation">,</span>
  context<span class="token operator">:</span> Component<span class="token punctuation">,</span>
  children<span class="token operator">:</span> <span class="token operator">?</span>Array<span class="token operator">&lt;</span>VNode<span class="token operator">&gt;</span><span class="token punctuation">,</span>
  tag<span class="token operator">?</span><span class="token operator">:</span> string</span>
<span class="token punctuation">)</span><span class="token operator">:</span> VNode <span class="token operator">|</span> Array<span class="token operator">&lt;</span>VNode<span class="token operator">&gt;</span> <span class="token operator">|</span> <span class="token keyword">void</span> <span class="token punctuation">{</span>
  <span class="token keyword">if</span> <span class="token punctuation">(</span><span class="token function">isUndef</span><span class="token punctuation">(</span>Ctor<span class="token punctuation">)</span><span class="token punctuation">)</span> <span class="token punctuation">{</span>
    <span class="token keyword">return</span>
  <span class="token punctuation">}</span>
 <span class="token comment">// 构建子类构造函数 </span>
  <span class="token keyword">const</span> baseCtor <span class="token operator">=</span> context<span class="token punctuation">.</span>$options<span class="token punctuation">.</span>_base

  <span class="token comment">// plain options object: turn it into a constructor</span>
  <span class="token keyword">if</span> <span class="token punctuation">(</span><span class="token function">isObject</span><span class="token punctuation">(</span>Ctor<span class="token punctuation">)</span><span class="token punctuation">)</span> <span class="token punctuation">{</span>
    Ctor <span class="token operator">=</span> baseCtor<span class="token punctuation">.</span><span class="token function">extend</span><span class="token punctuation">(</span>Ctor<span class="token punctuation">)</span>
  <span class="token punctuation">}</span>

  <span class="token comment">// if at this stage it's not a constructor or an async component factory,</span>
  <span class="token comment">// reject.</span>
  <span class="token keyword">if</span> <span class="token punctuation">(</span><span class="token keyword">typeof</span> Ctor <span class="token operator">!==</span> <span class="token string">'function'</span><span class="token punctuation">)</span> <span class="token punctuation">{</span>
    <span class="token keyword">if</span> <span class="token punctuation">(</span>process<span class="token punctuation">.</span>env<span class="token punctuation">.</span><span class="token constant">NODE_ENV</span> <span class="token operator">!==</span> <span class="token string">'production'</span><span class="token punctuation">)</span> <span class="token punctuation">{</span>
      <span class="token function">warn</span><span class="token punctuation">(</span><span class="token template-string"><span class="token template-punctuation string">`</span><span class="token string">Invalid Component definition: </span><span class="token interpolation"><span class="token interpolation-punctuation punctuation">${</span><span class="token function">String</span><span class="token punctuation">(</span>Ctor<span class="token punctuation">)</span><span class="token interpolation-punctuation punctuation">}</span></span><span class="token template-punctuation string">`</span></span><span class="token punctuation">,</span> context<span class="token punctuation">)</span>
    <span class="token punctuation">}</span>
    <span class="token keyword">return</span>
  <span class="token punctuation">}</span>

  <span class="token comment">// async component</span>
  <span class="token keyword">let</span> asyncFactory
  <span class="token keyword">if</span> <span class="token punctuation">(</span><span class="token function">isUndef</span><span class="token punctuation">(</span>Ctor<span class="token punctuation">.</span>cid<span class="token punctuation">)</span><span class="token punctuation">)</span> <span class="token punctuation">{</span>
    asyncFactory <span class="token operator">=</span> Ctor
    Ctor <span class="token operator">=</span> <span class="token function">resolveAsyncComponent</span><span class="token punctuation">(</span>asyncFactory<span class="token punctuation">,</span> baseCtor<span class="token punctuation">,</span> context<span class="token punctuation">)</span>
    <span class="token keyword">if</span> <span class="token punctuation">(</span>Ctor <span class="token operator">===</span> <span class="token keyword">undefined</span><span class="token punctuation">)</span> <span class="token punctuation">{</span>
      <span class="token keyword">return</span> <span class="token function">createAsyncPlaceholder</span><span class="token punctuation">(</span>
        asyncFactory<span class="token punctuation">,</span>
        data<span class="token punctuation">,</span>
        context<span class="token punctuation">,</span>
        children<span class="token punctuation">,</span>
        tag
      <span class="token punctuation">)</span>
    <span class="token punctuation">}</span>
  <span class="token punctuation">}</span>

  data <span class="token operator">=</span> data <span class="token operator">||</span> <span class="token punctuation">{</span><span class="token punctuation">}</span>

  <span class="token comment">// resolve constructor options in case global mixins are applied after</span>
  <span class="token comment">// component constructor creation</span>
  <span class="token function">resolveConstructorOptions</span><span class="token punctuation">(</span>Ctor<span class="token punctuation">)</span>

  <span class="token comment">// transform component v-model data into props &amp; events</span>
  <span class="token keyword">if</span> <span class="token punctuation">(</span><span class="token function">isDef</span><span class="token punctuation">(</span>data<span class="token punctuation">.</span>model<span class="token punctuation">)</span><span class="token punctuation">)</span> <span class="token punctuation">{</span>
    <span class="token function">transformModel</span><span class="token punctuation">(</span>Ctor<span class="token punctuation">.</span>options<span class="token punctuation">,</span> data<span class="token punctuation">)</span>
  <span class="token punctuation">}</span>

  <span class="token comment">// extract props</span>
  <span class="token keyword">const</span> propsData <span class="token operator">=</span> <span class="token function">extractPropsFromVNodeData</span><span class="token punctuation">(</span>data<span class="token punctuation">,</span> Ctor<span class="token punctuation">,</span> tag<span class="token punctuation">)</span>

  <span class="token comment">// functional component</span>
  <span class="token keyword">if</span> <span class="token punctuation">(</span><span class="token function">isTrue</span><span class="token punctuation">(</span>Ctor<span class="token punctuation">.</span>options<span class="token punctuation">.</span>functional<span class="token punctuation">)</span><span class="token punctuation">)</span> <span class="token punctuation">{</span>
    <span class="token keyword">return</span> <span class="token function">createFunctionalComponent</span><span class="token punctuation">(</span>Ctor<span class="token punctuation">,</span> propsData<span class="token punctuation">,</span> data<span class="token punctuation">,</span> context<span class="token punctuation">,</span> children<span class="token punctuation">)</span>
  <span class="token punctuation">}</span>

  <span class="token comment">// extract listeners, since these needs to be treated as</span>
  <span class="token comment">// child component listeners instead of DOM listeners</span>
  <span class="token keyword">const</span> listeners <span class="token operator">=</span> data<span class="token punctuation">.</span>on
  <span class="token comment">// replace with listeners with .native modifier</span>
  <span class="token comment">// so it gets processed during parent component patch.</span>
  data<span class="token punctuation">.</span>on <span class="token operator">=</span> data<span class="token punctuation">.</span>nativeOn

  <span class="token keyword">if</span> <span class="token punctuation">(</span><span class="token function">isTrue</span><span class="token punctuation">(</span>Ctor<span class="token punctuation">.</span>options<span class="token punctuation">.</span>abstract<span class="token punctuation">)</span><span class="token punctuation">)</span> <span class="token punctuation">{</span>
    <span class="token keyword">const</span> slot <span class="token operator">=</span> data<span class="token punctuation">.</span>slot
    data <span class="token operator">=</span> <span class="token punctuation">{</span><span class="token punctuation">}</span>
    <span class="token keyword">if</span> <span class="token punctuation">(</span>slot<span class="token punctuation">)</span> <span class="token punctuation">{</span>
      data<span class="token punctuation">.</span>slot <span class="token operator">=</span> slot
    <span class="token punctuation">}</span>
  <span class="token punctuation">}</span>

  <span class="token comment">// 安装组件钩子函数，把钩子函数合并到data.hook中</span>
  <span class="token function">installComponentHooks</span><span class="token punctuation">(</span>data<span class="token punctuation">)</span>

  <span class="token comment">//实例化一个VNode返回。组件的VNode是没有children的</span>
  <span class="token keyword">const</span> name <span class="token operator">=</span> Ctor<span class="token punctuation">.</span>options<span class="token punctuation">.</span>name <span class="token operator">||</span> tag
  <span class="token keyword">const</span> vnode <span class="token operator">=</span> <span class="token keyword">new</span> <span class="token class-name">VNode</span><span class="token punctuation">(</span>
    <span class="token template-string"><span class="token template-punctuation string">`</span><span class="token string">vue-component-</span><span class="token interpolation"><span class="token interpolation-punctuation punctuation">${</span>Ctor<span class="token punctuation">.</span>cid<span class="token interpolation-punctuation punctuation">}</span></span><span class="token interpolation"><span class="token interpolation-punctuation punctuation">${</span>name <span class="token operator">?</span> <span class="token template-string"><span class="token template-punctuation string">`</span><span class="token string">-</span><span class="token interpolation"><span class="token interpolation-punctuation punctuation">${</span>name<span class="token interpolation-punctuation punctuation">}</span></span><span class="token template-punctuation string">`</span></span> <span class="token operator">:</span> <span class="token string">''</span><span class="token interpolation-punctuation punctuation">}</span></span><span class="token template-punctuation string">`</span></span><span class="token punctuation">,</span>
    data<span class="token punctuation">,</span> <span class="token keyword">undefined</span><span class="token punctuation">,</span> <span class="token keyword">undefined</span><span class="token punctuation">,</span> <span class="token keyword">undefined</span><span class="token punctuation">,</span> context<span class="token punctuation">,</span>
    <span class="token punctuation">{</span> Ctor<span class="token punctuation">,</span> propsData<span class="token punctuation">,</span> listeners<span class="token punctuation">,</span> tag<span class="token punctuation">,</span> children <span class="token punctuation">}</span><span class="token punctuation">,</span>
    asyncFactory
  <span class="token punctuation">)</span>
  <span class="token keyword">if</span> <span class="token punctuation">(</span>__WEEX__ <span class="token operator">&amp;&amp;</span> <span class="token function">isRecyclableComponent</span><span class="token punctuation">(</span>vnode<span class="token punctuation">)</span><span class="token punctuation">)</span> <span class="token punctuation">{</span>
    <span class="token keyword">return</span> <span class="token function">renderRecyclableComponentTemplate</span><span class="token punctuation">(</span>vnode<span class="token punctuation">)</span>
  <span class="token punctuation">}</span>

  <span class="token keyword">return</span> vnode
<span class="token punctuation">}</span>
</code></pre></div><p>稍微提下<code>createComponent</code>生成<code>VNode</code>的三个关键流程：</p> <ul><li>构造子类构造函数<code>Ctor</code></li> <li><code>installComponentHooks</code>安装组件钩子函数</li> <li>实例化 <code>vnode</code></li></ul> <h3 id="小结"><a href="#小结" class="header-anchor">#</a> 小结</h3> <p><code>createElement</code> 创建 <code>VNode</code> 的过程，每个 <code>VNode</code> 有 <code>children</code>，<code>children</code> 每个元素也是一个<code>VNode</code>，这样就形成了一个虚拟树结构，用于描述真实的<code>DOM</code>树结构</p> <h2 id="参考文献"><a href="#参考文献" class="header-anchor">#</a> 参考文献</h2> <ul><li>https://ustbhuangyi.github.io/vue-analysis/v2/data-driven/create-element.html#children-%E7%9A%84%E8%A7%84%E8%8C%83%E5%8C%96</li> <li>https://juejin.cn/post/6876711874050818061</li></ul></div> <footer class="page-edit"><!----> <div class="last-updated"><span class="prefix">更新时间:</span> <span class="time">12/14/2021, 10:12:35 AM</span></div></footer> <div class="page-nav"><p class="inner"><span class="prev">
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